SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9efbe55c777a736e6b64707fee721137ccec686625a9881ab90ecd63d8bd9b07' 
  AND token = 'SJYYIiuJqlLFTK9tr3dje+4sG73r5f9+JB4b4vmycT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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