SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edfbf5a732dcea784a2d35e11990894fa58d57ab858bc2519156184924bc91c9' 
  AND token = 'mH8hpPr5VxAC88gEZ4qBIV/0KOfTi6vK0Zal31v/JfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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