SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49c140b7a2dd436bae8bd74e2a6186a5d76ba141b6c36f96c7516ec5367db016' 
  AND token = '3EdkPNkz4FHvCTSfCTyhfzO7cNDn5MiNfaZmbImhGCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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