SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5461881e10f1ce22c51be29cac712f3b93a48a218998f846c2be14399efad3a' 
  AND token = 'tHaACEShF+JXAZfV3oCip7Qd+/IYBvzEUw9VQjZ14QA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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