SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c31ae3b1026691d50704bf0d986cf45933f5308d12e5041f1416ea7af7deb3b1' 
  AND token = 'ePnV+YXcX4VQgJPmm3xJPJJoAeRHj+evi/lBcoqKMJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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