SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e373a1f48c9b7a0c4599ec22cc94a921fda08de01c98da5316229a762dca560d' 
  AND token = 'kwGBh6x4FD522xTusxhz0mku3KQCbGFq4D3vN+Kxp84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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