SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2631f25770318525a28aa21ca8c22ac22f88c8539c66b606312a858a21bdd3d' 
  AND token = 'rSRES7r5MDX54XcEontPt35hQVEYDpNOV1bRXXZrqkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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