SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2ee2753d8fd312c6aff1b565035b338fa04a8933b0ea20f0b62c7db74a56381' 
  AND token = 'oAK7mXatHUtd5dF35r/DtEWRpydX0fsgqFVRiOz14h0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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