SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a842c734526697f0e0ba303824bff0693ed72ad4cfb8418aae2308bc9b82f65c' 
  AND token = 'kmsJtqlBqdwvtyvcbvUqOZlxu3zWps+upKS7Gozzbrc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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