SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86ac90ca6820682ded3a6d2125bc782cf15b0a6ad6dfbd337f84a9426bd25f76' 
  AND token = 'iquu0xb24EffdSGWMoWTfyjcJp4dsbK7NoiWfWQvqQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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