SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2a4f90d9244c89832c722daaae9da8ff75bf1b1fdcef294c0725fe6450c6475' 
  AND token = 'Z+h38CIz0DPW2UaLCTYjJBK9xZJotZV1eVr/AoNNMzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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