SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea72bbef54a50ccd923f6a2e6b7ae78531f2331cca96be4dd90df784ccb9c4f3' 
  AND token = 'fS80xFVogbG/Me9EN+nL2iwpSRArV949bFF/5hObpqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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