SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96484953dedebe847dd420969628d78b0f39647ee3ccfea8a029df074c304b75' 
  AND token = 'm8Afcw2ZcPOMBLoEJ2087KDUMsQIOrrk4/ZX7Kx9MMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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