SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '647b62a9252ef893aec3242c825355b54dbaad5adeb011cfcaef15b2c6cfaaa2' 
  AND token = 'kHFZq3SHjOydPM+BfZPDLFFusarAcFjvmKUPBBpmCE0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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