SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c094a20c6342270d4931d1693251132a709aa6c243636eb1b45eda5087e9a92c' 
  AND token = 'vDcKfWafnNplWC0sb4rCJeQ/zskNuIO+tATnxoUAHg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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