SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78c5da4ebba6e6d2e072effb25effa1f3d0af0b6d1ac54b22dc1dd836a67119d' 
  AND token = 'LMQONLLQc2jligIri1bi2f4duWi/SYkPAoG9elmbnnk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00062

JSON explain

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