SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88fad3d7a37221863bc6062f6f76f7542ec875c0a7e094855845f9e374c1a970' 
  AND token = '5s6ElaTUjx160J3aTsDxdp/Gf3F5dS/OKE2myaUOaWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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