SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88326132cf161106aee88362947214cfb4753aed090dbd9e8e2a8facba3a2088' 
  AND token = 'PvddrhgTZ2mQGhOx+TF3fDgXw/3YxDP5S2y2+MOPCPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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