SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9e699ae10f53dbe96a3f88ebbbca85bb9e3bb699bb6e9ef76a0030aeb54c75' 
  AND token = 'CICYjLSUsTdA9Ocr80F5VBcoiUwhC8B+/NqZECyniWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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