SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4501ea78c18c27ed8fce53351739cfce8f98f42026966b4a9ac5490930d25f4d' 
  AND token = 'LFskR+M90JhzY8LlpzJmgM2H3rdSFvjBxCgcPG0WD5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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