SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5b700bbb145d3a2d763e250851c4b894a2b31cff84be0a6949d3271c37d66d1' 
  AND token = 'UZj0AJeArHZrLgRt1V8w+FBQpYgNls/h3UHyMSI0kTU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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