SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12907f2a1f66545f0083890ef5332856cd3b2e2071d64b9f193855c1a6587458' 
  AND token = 'uinwzec20syjHrdGmd4snpvpz+gbzqeRg9JgZenjaNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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