SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3918a04b1ee87122655502e72702cf43f458779d949c1ec30d18bd42efd332d1' 
  AND token = 'OFTnRecoCfrwv/Ft+BHG21D4MWxDVuLt5a6o/NfmrmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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