SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e82fbff67cc34f1dcb0703d16331afc84f894e5f4f8331559f0890758bd30f5' 
  AND token = 'J6kXXDCT3kr66nAn3XJZdiQGsQQde3kxQeItq9sLC8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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