SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b29c5c4bbed7f8dd03ef7c5c661a9a65a0110f129d8ff176de9632fabadc180f' 
  AND token = 'OAU8h9J9KpQYZjtcyFKiVnOQKupm0NyMF1MtMedHNFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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