SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c760105c216e46bf9f84257ffc629a7242dbb1e2b52454fd502b6a97ebb831cd' 
  AND token = 't9JK+hr1M72W7NNfGEkhW4dgnsS2R1+QuJkBywXGp7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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