SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '680729359138d5a9e985ea81bee34b2e30a442605089f125d78522a94d31085b' 
  AND token = 'cphABIpnfSX4REoTGk7tHxuSM+67Pk7eAZYzd0dKpDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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