SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '773ee5e2f9233d687b0a987109fdb03c676541edfaac2b7b6f04a37001fbd9e2' 
  AND token = 'lji/kYkgLVRZbIAY3m3kOMzRTVz70INCjcq9Pc4WV/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}