SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c57cefbd2b0fbcfae0ba4d1a1a5de0a4d837273f9d766d368954508e59b7ee8' 
  AND token = '6j6bkkiJSg9uXm7LW1K4xEBQL47p+DufPgmY0lVDGpc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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