SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bd3dd212451730e75356cf4a13c4955e6f5971b3558b4bf14aeaa90328bd838' 
  AND token = 'xGmSaS9G586vbcNRljU77KJojXPg/WN0ZYovkr8dd7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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