SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26bb642ac49825d1d8d87443c3c88261a3a1af09477e9a0f09f329c834b0e0a2' 
  AND token = 'B3kyw4cEgevibGy24feHhFpQMSdAot/I3PUncQXoCk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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