SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '309e17c690f46bf431db151b24f1ffdce9afa92b2e00ea29b0c7152de3d88a1a' 
  AND token = '4GlIPb6vv7mIfVYGYZRgEJXAuD2pRchkKHnli4AF9+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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