SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bac964215e15feb26f9c90e984d2b49500d9e08a551a95bd5af1b5ae2d9fb5b' 
  AND token = 'r6oiw1tF6zmZ11BA0XJj7QqPfgTmRu0p4/Ay8dB77HE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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