SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e8b13bd7807ab701d7320cefccbd4d037c05dcc2f4d79db6896f123aac71b3d' 
  AND token = '6NuRxhSgzvh6ZpNSSyP5PCMjjKlawy27rtAw5glKwKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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