SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ee89534d3264e3dfee0a85d101295526c587ef739b13c092bb975db253febdd' 
  AND token = '6ci1P5KAgwrJ2RJuWbTWzlp0UC7gsMeqSyfVFI+b1Ds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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