SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c623a16533d83e139167bf9a6e6ace04bc121e92960e922254191bf1c1208a5' 
  AND token = 'CsTP2Ggb5BM2xXC9OrOWjfFKgiAvXxpQGMwvD6nhiho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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