SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd148bfca3782227d69c0e3a1206f85eca081270c5ca100467655e9237957d76' 
  AND token = 'PL8EuRvUnxIYhbAPcz4oVPEXYdrLmvWhrPsvrG/hpkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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