SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8c9ccf1b172c5255d4fa80e5f6b9c05a5b0decf764e3bcfbe23ef18b14c0292' 
  AND token = 'kztsNSojmohpvZvw7q7ZgW5K79P4eJ6TqHFP/Sbqziw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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