SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c475128a17e43760c865339d7943090559a14ba9f8a2640330bfb5f5e327f07e' 
  AND token = 'WSSst2kpj6C/ouwrn63jzW03P58KtIMgVMpMeMccExI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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