SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1c910887206a1d5aed6b315913f9959c9ddbd05b65f1089ca6176f65e85f3eb' 
  AND token = 'eSYl+zCrtm5PKNAFo9bROEZvxkrE6p+VRLkgRHfDHbc=' 
  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"
    }
  }
}