SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42a6c9b9ea6fb0af085a507736017ab1696a69e22c9ed773a722b177b6dbe034' 
  AND token = 'mGyitwiiLBIErOnMYECyayZvl33249GHkPg9o9FyCyI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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