SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '543c1796a2fcd7460a31ef1e1cbb5676e49832bf74f7a94acf12090231269145' 
  AND token = 'XJrFS7q65nYXCLaSpPB3pInFgsBsXlmbqpittQ8e7NU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}