SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9187a2a3114849acbaa98bcb73b9acf9a4c28a64d7a0332e5a8be1e8c4407248' 
  AND token = 'BNVxElIpuYcxvIX2eNINc0A6lZVPdfuRGTj/wBpg+i4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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