SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5750480377888e6731c1c5e38501b066c330e096945c3c8ba1a895c3de9cf0f' 
  AND token = 'Kf1chpek2HOFAajM+Sk9IBRtEMGK80Ez4EIHXMMjBzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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