SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c5618b20c8c861deb762d3654b4fb55a38a22a6a5cebac387ef694879329f0b' 
  AND token = 'ld9nkOrCcMqBLYD3WosRlpObdhAc0BZJn9leChaQQAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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