SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41290e2c2eb8bd0984854abfd76ba5d15720a3971a6477ece0f2043ebd286f43' 
  AND token = 'Di/+iL0yliGgw+upiZpghhFs2dcFEqFSUCsW1XE3Y5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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