SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fc3cd602cc39b5f3998df7fa7cd0b5e89555a0b7f63d4ad4116fcb8629262887' 
  AND token = 'vszTthwrFJG+u/u8QwXEKLelnp4uEW2UUPsKAocdIqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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