SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47ed6a26caa933f2897ce87159d3f540b2705cf83f31986d3cd3cf55bacf79af' 
  AND token = 'pwJQ/pbBE9rPYzIGTkLP6lbVZBZMfvtTcL4aSSSnjZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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