SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7231131110a1c91c05293cf5733298c9a2f478f74416a0c0dd4e53c41e4f576' 
  AND token = 'fkAyKEzz4lkXJ6wDI8coMPg9KxtUfWImljzQw2PNiLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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