SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5d43d454db693eca82856d9344b372797486cdf5ac37a4a287c7c4f32b5147f' 
  AND token = 'kJaAj/AZHgBQd+ypCkx/GJs+Qyihqak+Scm+cSiUXLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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