SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9dfb521f0cbd67fb3b6ca3e8be0bdfad2387ed64a20859989da943ab576bd97b' 
  AND token = 'O4d0XaYOiN54dmZapqdmCRz5+nsBhiZCDduvSxAINxQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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