SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4f0c975db9bdb0933953991f2566c067c9599b237177d930b56a2571af17b64' 
  AND token = 'PEOpoFMJhlP4zgB432obXrmN1MJOBjQfpiotPuvOLWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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