SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b662653bff944d380af72159d319bfa53e3a7bfbaf83d314eb2a2e143d840572' 
  AND token = 'xasVdivqur7CSMnM1FKJRTcPARos/a1YmeOPO/5+aCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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