SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '382b3b03ed1298dd485a06cab805b68565bdd90d254d9cebfed1cc06933bdbc9' 
  AND token = 'udUOZXSoQ+Mi9tKLpBZ1JtjfaulNuczhMauPIrDmsBU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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