SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2be5548e309e6dff7b25b32f2357875ea6906fa5cedf21c2fe06acf0f52e295' 
  AND token = 'ZXGUUCB6nk6FzFNSCheb8Ymhqb279a8o2i9A0CfHZzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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