SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdf79d0775b90bb14640dfe39d2b3063b9b8b52147ae8636388245bf598710fb' 
  AND token = 'kNcI+Jwb2Bq17zvLrgcEo5IBNK2Lu+Fjg1ei6q1Xtw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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