SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '314e8cc7626ff893ef654e8a093804e4ac4df29d98fb2abbae6ba7a97944d8bc' 
  AND token = 'BIg2/YaidUkLUzjhYmMq3yRsUGQc2UwuTrPVUxOOCAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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