SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e27fe1ce80fc8e26d41017e18d80ca8ef4b16e0d4761cb6bd7591b6bd2d93ad9' 
  AND token = 'tNeacp1qydTBXvgTQmV5ZcynPLYDzA5yZiT1j7Mlc3o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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