SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c98e5c8d50452ba4cbc9cddd36b17181126b435eca0d60c8414a8094d8cc9cd1' 
  AND token = 'mGUmUnrcG40x5WYSi9R43ilmEGMxmrgSRs+ihVRjANY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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