SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7a93e15a7deeebe4a63c414d2e03f78660cec047b6fe4c3962a7bb26a7c9557' 
  AND token = 'JPZr1d6fUmqvNvvYUvl+EYVE8VHaGbakkqCcvAFmFYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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