SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c2627ad7abf4e9ab3b122639fd8279f9cab26ef7f8b50249b915e92a445c59d' 
  AND token = 'UdACi+b6d/KMPCm/OXDSMIDJ+CUrpejZM8jTwYBCFHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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