SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36d232b753f472d2e3126d831ee8d1e90c458c62f0a15765ac7edf0720026531' 
  AND token = 'NjXNeMgRSWZ3mJFDYpuhrTU6ekiflfxWlsdPSwdM/EQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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