SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab3c51e92b65d3fadfb7dc66489b80554be1194d81811ad384b794fc94cf3250' 
  AND token = '1HpF3eb5t2cdYq90sPyAoxio/Qpj0DSQnZJ+ZPU3ecI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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