SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b500dbac047e86d52ec539bea3be6dd43d2ae1cb6e443e12a29625d5c402302' 
  AND token = 'ycqHIzLQkxqC7i+R9DR5YqE+saBktmabRpJLKruz60I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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