SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96cb6e0bbb8931a8d706dc26e195e48378f4aed7516bb398b6112e5307f07edc' 
  AND token = 'VrXMZd00kRO6qWQhxFvuZvQsBJrGNY08ihUG7BNiOGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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