SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8634a1b997c4c92f0506d3cb35501a816c536e48daa113d00dd23b084fb6dca' 
  AND token = '9Ghz8ZYCvcTRsGwwygzm4pWNs4gEYMs0epp02CMU3qA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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