SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0ea1f52c9673801ee8728d284247868e029b05c89627cb165d06ee9871c04187' 
  AND token = 'fZlkVl/E/XQNPY/Ivpn9HsbK+ke7g32pwhzHVFUUwWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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