SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba5604fe6c8215b83e8e06f53cfb98d9095acafa668a69c382a2b21d4e7437f4' 
  AND token = 'SkLj/7BMXPwqOznTc14ss+vMjiCoUu+SPvvFzAiXH24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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