SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '211e29bbe966c09a7b9692af94b63199aee4405f36104bb9d5dc18d522e9ba94' 
  AND token = 'eAISttpHtrVgDQJRV9nVO8XJ03m5p632m9EFYxg0F5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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