SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c52d71531f7334f9a51788e61534c2b7a6d497ac57561f13bbef51b7840bb6c4' 
  AND token = 'cQVKgqvF7VNZXgiblOBxCGdgf+2075HBAvZWjvNj1bI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}